1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor device having flexibility.
2. Description of the Related Art
It has been required to manufacture semiconductor devices at low cost, and development of elements such as thin film transistors, memories, and solar cells for control circuits, memory circuits, or the like has been extensively carried out in recent years (for example, Reference 1: Japanese Published Patent Application No. 2004-47791).
Various applications of semiconductor devices having elements such as thin film transistors, memories, and solar cells are expected, and using flexible plastic films is attempted in pursuit of reduction in size and weight.
Since plastic films have low heat resistance, it is necessary to decrease the highest temperature in a process. Therefore, a method for manufacturing a semiconductor element is limited. Accordingly, the semiconductor devices using plastic films are manufactured by an evaporation method or a sputtering method using a metal mask.
A technique is suggested, in which after a polyimide layer is formed over a glass substrate and a layer having a fine element is formed over the polyimide layer, the polyimide layer is irradiated with a laser beam from the glass substrate side, and the polyimide layer and the layer having the fine element are separated from the glass substrate to form a display device having flexibility (Reference 2: French and others (Ian French, David McCulloch, Ivar Boerefijin, Nico Kooyman), SID 2005 Digest, U.S.A., 2005, pp. 1634-1637)